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        Tue, 25 Oct 2016 21:03:44 -0700 (PDT)
Subject: Re: [PATCH] Fix x86 atomic_fetch_xor_release.
To: Torvald Riegel <triegel@redhat.com>
References: <1eeffe37-c4ec-fef7-537b-9ad17129b6c0@redhat.com>
 <1476788563.14800.38.camel@localhost.localdomain>
Cc: GNU C Library <libc-alpha@sourceware.org>
From: Carlos O'Donell <carlos@redhat.com>
Message-ID: <0518fd92-831d-0424-3ad6-79ced2b6b287@redhat.com>
Date: Wed, 26 Oct 2016 04:04:00 -0000
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On 10/18/2016 07:02 AM, Torvald Riegel wrote:
> On Mon, 2016-10-17 at 23:18 -0400, Carlos O'Donell wrote:
>> Torvald,
>>
>> No code uses atomic_fetch_xor_release except for the upcoming conditional
>> variable rewrite. Therefore there is no user visible bug here.
>>
>> The use of atomic_compare_and_exchange_bool_rel is removed (since it doesn't
>> exist anymore), and is replaced by atomic_compare_exchange_weak_release.
>>
>> We use weak_release because it provides better performance in the loop
>> (the weak semantic) and because the xor is release MO (the release semantic).
>>
>> We don't reload expected in the loop because atomic_compare_and_exchange_weak_release
>> does this for us as part of the CAS failure.
>>
>> It is otherwise a fairly plain conversion that fixes building the new condvar
>> for 32-bit x86.
>>
>> I have pushed the new condvar into Fedora Rawhide for testing.
>>
>> OK to checkin?
> 
> OK.
> 

Checked in. Verified it fixes everything with the other dependent
patches applied.

-- 
Cheers,
Carlos.